JPS6034032B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system, and particularly to a refrigeration system suitable for a hot gas bypass defrosting system.

In a conventional refrigeration system equipped with a hot gas bypass defrosting device, the discharge side of the compressor and the inlet side of the evaporator are connected by bypass piping, and a solenoid valve is interposed in the middle of this bypass piping to prevent defrosting. The defrosting method used was to open this solenoid valve and bypass the discharged gas from the compressor to the evaporator. In this conventional system, the discharge gas of the compressor is bypassed from the discharge side to the evaporator, and at the same time, this bypass piping is connected to the inlet of the condenser by piping, so it is affected by the temperature and pressure of the condenser. Particularly in the case of an air-cooled condenser, if the temperature around the condenser is low, the high-temperature gas discharged from the compressor will be collected in the condenser, and sufficient discharge gas will not reach the evaporator. Conversely, when the ambient temperature of the condenser is high, the refrigerant in the condenser also flows into the evaporator through the bypass circuit,
There was a drawback that defrosting performance became unstable due to excessive refrigerant in the evaporator. This invention was invented to eliminate the above-mentioned drawbacks, and its purpose is to provide a refrigeration system that can perform stable hot gas bypass defrosting regardless of the external temperature or pressure of the condenser. shall be.

In order to achieve the above object, the present invention uses a 40,000 valve as a valve to switch the refrigeration cycle from cooling operation to hot gas bypass defrosting operation, and disconnects the discharge side of the compressor and the condenser during hot gas bypass defrosting operation. In addition, the condenser is connected to the suction side of the compressor by a pongee pipe, and the condenser is gradually replenished from the condenser to the suction side of the compressor.

An embodiment of the present invention will be described below with reference to the drawings.

1 is a compressor whose discharge side is connected to a four-way valve 2, and the discharge side path is switched to a condenser 3 as shown by a solid line during cooling operation, and to a check valve 8 as shown by a broken line during defrosting operation.

The outlet side path of the condenser 3 is connected to the expansion valve 4.
The outlet route of the evaporator 5 is connected to the evaporator 5, and the outlet route of the evaporator 5 is connected to the suction side of the compressor 1 via the accumulator 6. Further, the check valve 8 can flow only in the direction of the dashed arrow, and its outflow side is connected to a path connecting the expansion valve 4 and the evaporator 5. Further, a pongee pipe 7 is connected to the outflow side of the evaporator 5, and this thin pipe is connected to the other passage of the four-way valve 2, and during cooling operation, the connection path is connected to the check valve 8 side as shown by the solid line. During frost operation, switch to condenser 3. Solid line arrows indicate the flow direction of cold soot during cooling operation, and dashed line arrows indicate the flow direction of cold soot during defrosting operation. During cooling operation, the discharged refrigerant gas compressed by the compressor 1 flows into the condenser 3 via the four-way valve 2, where it is cooled and liquefied, and then flows through the expansion valve 4, as shown by the solid arrow. The soot is depressurized and becomes low-pressure cold soot and flows into the evaporator 5.
The soot gas which absorbs heat from the fluid to be cooled and vaporizes in the evaporator 5 is sucked into the compressor 1 via the accumulator 6. As the cooling operation progresses, frost forms on the evaporator 5.

As frosting progresses, the cooling performance decreases, so the operation is switched to defrosting mode as appropriate. For defrosting operation, switch the four-way valve 2 as indicated by the broken line. The refrigerant flows in the direction of the dashed arrow. The high-temperature, high-pressure discharge gas compressed by the compressor 1 passes through the four-way valve 2 and the check valve 8, and the entire amount directly flows into the evaporator 5, heating the evaporator 5, so that the frost attached to the surface is melted. The soot gas is cooled, a portion of which is liquefied, and is sucked into the compressor 1 again through the accumulator 6, forming a hot gas bypass defrosting cycle. At this time, the evaporator 5 performs a condensing action, so the evaporator 5 requires a larger amount of piping than during the cooling operation, but the four-way valve 2 is connected to the inlet side of the condenser 3 and the outlet side of the evaporator 5. Since they are connected by a narrow tube 7, the refrigerant gas in the condenser 3 is gradually replenished into the defrosting cycle through the narrow tube 7, and optimal hot gas bypass defrosting is performed. The check valve 8 in the above embodiment is a flow path controller, and instead of the check valve, it may be an electromagnetic valve that is turned on only during defrosting. FIG. 2 shows another embodiment, in which a capillary tube 9 is connected to the flow path controller in parallel with a check valve 8, and other parts are the same as those in the embodiment shown in FIG. 1, so the same symbols are used. and the explanation thereof will be omitted.

During cooling operation of the refrigeration system having the above structure, the compressor discharged from the compressor 1 flows through the compressor 1, the four-way valve 2, the condenser 3, the expansion valve 4, the evaporator 5, the accumulator 6, and the compressor 1. During this operation, a very small portion of the refrigerant whose pressure is reduced by the expansion valve 4 flows through the capillary tube 9, passes through the four-way valve 2, and flows into the accumulator 6 via the string pipe 7. As mentioned above, in this embodiment, a small amount of low-pressure refrigerant flows into the four-way valve 2, so that the four-way valve 2 is cooled below the permissible temperature, which has the effect of ensuring the switching operation. As explained above, according to the present invention, during hot gas bypass defrosting, the discharge side of the compressor and the condenser are separated, and the condenser and the defrost cycle are connected with a pongee pipe, so that the surrounding conditions of the condenser are controlled. Moreover, the refrigerant in the condenser can be gradually replenished into the defrosting cycle without being affected, and a stable defrosting action can be performed.

[Brief explanation of the drawing]

FIG. 1 is a cycle configuration diagram of a refrigeration system showing one embodiment of the present invention, and FIG. 2 is a cycle configuration diagram showing another embodiment. 1... Compressor, 2... Four-way valve, 3... Condenser, 4
... Expansion valve (throttle device), 5... Evaporator, 6...
Accumulator, 7... Thin tube, 8... Check valve (flow path controller), 9... Capillary valve. Ta'zu Ta Z style

Claims (1)

[Scope of Claims] 1. A discharge side path of the compressor is connected to one switching flow path of a four-way valve, and is switchably connected to an evaporator inlet side path via a condenser or a flow path controller, The condenser throttling device, the evaporator, and the compressor suction side are sequentially connected with piping, the other end of the flow path controller is connected to the inlet side path of the evaporator, and a thin tube is connected to the outlet path of the evaporator, A refrigeration system characterized in that the other end is connected to the other switching channel of the four-way valve, and the condenser is connected to the outlet path of the evaporator via a thin tube during hot gas bypass defrosting. 2. The refrigeration system according to claim 1, wherein the flow path controller is a check valve. 3. The refrigeration system according to claim 1, wherein the flow path controller includes a check valve and a capillary tube connected in parallel.